The proposed study falls at the intersection of long-term care, the epidemiology of nursing home resident safety, and quality improvement activities that may lead to the reduction of harm in the nursing home setting. Specifically, we will study adverse events that occur among long-term care residents who transition from the nursing home setting to an acute care setting, and then who are discharged back to the same facility. For the purpose of this study, an adverse event is defined as harm or injury to a nursing home resident as a result of medical care, including the failure to provide needed care. The setting for this work will be a representative sample of 30 nursing homes drawn from across the six New England states. The study will be conducted in collaboration with the New England Quality Innovation Network - Quality Improvement Organization (NE QIN- QIO). We will take advantage of a practical method (the trigger tool methodology) to reliably identify, quantify, and characterize adverse events. The trigger tool methodology was developed by the Institute for Healthcare Improvement and employs triggers, or clues, to identify adverse events in medical records that can be ultimately linked to harm. The methodology has been adapted for use across a wide range of clinical settings. The specific aims of our study include the following: (1) to characterize the rates, types, severity, and preventability of adverse events that occur in the 45-day period post-hospital discharge among long-stay nursing home residents (long-stay = >100 days) who are hospitalized and return to the same facility; (2) to identify demographic, clinical, and functional resident characteristics associated with the occurrence of adverse events that occur in the 45-day period post-hospital discharge among nursing home residents who are hospitalized and return to the same facility; (3) to identify facility-level characteristics associted with the occurrence of adverse events that occur in the 45-day period post-hospital discharge among nursing home residents who are hospitalized and return to the same facility; and (4) to examine the impact of level of facility participation in the New England regional National Nursing Home Quality Care Collaborative on the occurrence of adverse events among nursing home residents who are hospitalized and return to the same facility. This study focuses on a setting of care characterized by variable quality and staffing, limited physician involvement, and inconsistent and often inadequate attention to patient safety and quality of care issues. The long range strategy underlying our efforts hinges on the expectation that by identifying safety concerns relevant to adverse events in nursing homes among residents during the very high-risk post-hospital discharge period, interventions may be developed to successfully combat systems that result in suboptimal care and outcomes in this highly vulnerable population.